[PATCH v3] Fix problem with imx_ddrc_sdram_size calc
joaze at westermo.com
Mon Nov 15 06:05:39 PST 2021
On Fri, Nov 05, 2021 at 10:39:27AM +0100, Sascha Hauer wrote:
> Hi Joacim,
> On Mon, Nov 01, 2021 at 01:11:09PM +0100, Joacim Zetterling wrote:
> > There was some issues with the imx_ddrc_sdram_size calculation.
> > If we compare the imx8mn DDR4 evk against the LPDDR4 variant in
> > code and in the datasheets, we see the following:
> > DDR4 LPDDR4
> > ========================
> > Bus width 16 16
> > Rank 1 1
> > Ranks 1 1
> > Banks 4 8
> > Banks grps 2 1
> > Rows 17 15
> > Col 10 10
> > This gives us the following problems:
> > 1. Bus width problem.
> > Does not support 16 bit SDRAM bus mode, only 32 bit supported
> > 2. Row size problem.
> > Only up to 16 bit row size support.
> > 3. Bank groups support.
> > Only support of 1 bank group.
> > 4. Bit count problem.
> > The imx_ddrc_count_bits function does not do a correct count.
> Could you split this into four patches fixing one problem at a time?
> I am not sure the problems can be separated from each other entirely,
> but splitting this up would make it much easier to understand the
> problems and also their fixes. We'll be glad having smaller patches
> should we ever have to look at this again.
I agree with You that the problems can not be separated completely.
But I will try to do my best. Do You prefer a patch set or separately
patches or a combination of them both?
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